The primary purpose of this study is to determine whether, in patients with acute coronary syndromes not taking statins in chronic administration, high doses of a hydrophilic statin (rosuvastatin) administered before coronary angiography and/or angioplasty, may exert a renal-protective effect by reducing the incidence of contrast nephropathy. Contrast induced nephropathy is defined as increased values of creatinine >= 0.3 mg/dl from baseline values, within 72 hours after contrast medium exposure.